<TABLE> <S> <C>

<PAGE>
<ARTICLE> 5
<CURRENCY> USD
       
<S>                           <C>                   <C>                  <C>                  <C>                  <C>
<PERIOD-TYPE>                 3-MOS                 12-MOS                9-MOS                6-MOS               3-MOS
<FISCAL-YEAR-END>                  DEC-31-1999           DEC-31-1998          DEC-31-1998          DEC-31-1998          DEC-31-1998
<PERIOD-START>                     JAN-01-1999           JAN-01-1998          JAN-01-1998          JAN-01-1998          JAN-01-1997
<PERIOD-END>                       MAR-31-1999           DEC-31-1998          SEP-30-1998          JUN-30-1998          MAR-31-1998
<EXCHANGE-RATE>                              1                     1                    1                    1                    1
<CASH>                              32,551,645            50,522,744           33,040,974          151,246,159          150,555,289
<SECURITIES>                                 0                     0                    0                    0                    0
<RECEIVABLES>                       57,223,948            49,073,840           39,944,931           29,716,528           29,604,269
<ALLOWANCES>                       (3,339,267)           (2,077,198)          (1,495,206)          (1,369,147)          (1,133,770)
<INVENTORY>                                  0                     0                    0                    0                    0
<CURRENT-ASSETS>                    92,579,695           102,394,461           82,660,722          187,835,271          182,435,544
<PP&E>                             169,419,156           150,727,612          155,651,101            6,986,214            5,610,089
<DEPRECIATION>                     (5,768,748)           (2,788,615)          (9,543,791)          (1,218,576)            (556,084)
<TOTAL-ASSETS>                     372,108,957           349,646,447          325,944,531          249,563,919          238,434,831
<CURRENT-LIABILITIES>               28,660,910            28,473,153           31,145,223           19,853,419           14,400,785
<BONDS>                            196,892,128           178,893,235          167,513,935          115,000,000          115,000,000
<PREFERRED-MANDATORY>                        0                     0                    0                    0                    0
<PREFERRED>                             71,000                73,000               73,000               73,000              183,000
<COMMON>                               901,878               900,729              883,636              883,273              876,314
<OTHER-SE>                         138,020,798           133,446,512          120,960,986          111,964,740          106,130,360
<TOTAL-LIABILITY-AND-EQUITY>       372,108,957           349,646,447          325,944,531          249,563,919          238,434,831
<SALES>                             50,717,834           146,918,478          103,417,296           63,812,349           29,645,703
<TOTAL-REVENUES>                    50,717,834           146,918,478          103,417,296           63,812,349           29,645,703
<CGS>                                        0                     0                    0                    0                    0
<TOTAL-COSTS>                       31,569,774            92,030,009           65,773,739           40,735,799           19,166,777
<OTHER-EXPENSES>                     7,346,930            24,181,801           17,162,961           11,152,284            5,199,594
<LOSS-PROVISION>                       721,804               887,753              801,238              703,133              122,617
<INTEREST-EXPENSE>                   3,515,544             8,493,224            5,886,303            3,666,710            1,838,128
<INCOME-PRETAX>                      9,748,209            30,625,409           21,120,652           12,748,902            5,770,146
<INCOME-TAX>                         3,850,543            12,556,418            8,659,468            5,226,777            2,400,381
<INCOME-CONTINUING>                  5,895,841            18,058,941           12,452,959            7,515,725            3,365,190
<DISCONTINUED>                               0                     0                    0                    0                    0
<EXTRAORDINARY>                              0                     0                    0                    0                    0
<CHANGES>                                    0                     0                    0                    0                    0
<NET-INCOME>                         5,895,841            18,058,941           12,452,959            7,515,725            3,365,190
<EPS-PRIMARY>                             0.33                  1.02                 0.71                 0.43                 0.19
<EPS-DILUTED>                             0.32                  0.99                 0.69                 0.42                 0.19
        


</TABLE>